A circuit module in which a sealing body including synthetic resin or the like seals around a mount component mounted on a circuit substrate has been used. Here, there exists a circuit module in which a surface of the sealing body is covered by a conductor and the conductor is used as a shield against an electromagnetic wave in the case where the mount component includes a wireless communication element, for example. The shield blocks electromagnetic interference from the mount component to the outside of the circuit module or electromagnetic interference from the outside of the circuit module to the mount component.
Furthermore, a circuit module in which a shield is disposed to separate a plurality of mount components with each other in order to block electromagnetic interference between the mount components, in the case where the mount components are mounted on the circuit substrate, has also been developed. Because the mount component is covered by the sealing body as described above, it is possible to form a trench (groove) by partially removing the sealing body and to form a conductor in the trench to use the conductor as a shield between the mount components.
Japanese Patent Application Laid-open No. 2010-225620 discloses a circuit module having a configuration in which a mold resin layer covering electronic components is covered by a conductive resin layer. In the circuit module, a slit separating the electronic components is formed on the mold resin layer and the conductive resin layer is filled in the slit. Accordingly, the conductive resin layer functions as a shield between the electronic components.